TUNA Lunch Talk:

Violette Impellizzeri


Molecular absorption in the cores of AGN

March 24

12:10PM, Room 230, NRAO, Edgemont Road


One of the fundamental concepts in the unified scheme of AGN is that both Seyfert 1 and Seyfert 2 galaxies harbour supermassive nuclear engines blocked from direct view by an optically and geometrically thick molecular tori. Searches for absorption lines of common molecules like CO and OH have mostly yielded non-detections. Before concluding that tori are not molecular, radiative excitation effects, which suppress the opacity in the lowest transitions, must be investigated. To explore these effects, we conducted a survey searching for excited OH from a sample of 31 Seyfert 2 galaxies. Here, I present the results of Effelsberg observations at 6031 MHz and 6035 MHz, yielding detections in five sources. I also present spectral line VLBI observations at 13.4 GHz which detected excited OH towards the cores of Cygnus A and NGC 1052, confirming the presence of a molecular torus. A subsample of the 31 Seyfert 2 galaxies was also observed at 6.7 GHz, yielding the first extragalactic detection of methanol. Finally, I present the exciting new discovery of a water maser at redshift 2.6, which is the most distant source where water has ever been found.